1. Field of the Invention
The present invention relates generally to a multi-range power supply unit or power pack for devices such as circuit breakers and contact systems. The multi-range power supply unit can have an automatic switching between ranges for different power supply voltages. The power supply unit has at least two input connections for a power supply voltage, two output connections for an output voltage and a rectifier circuit.
2. Background Information
Known power supply units include various types of direct current power supply units for connection to different power supply voltages.
German Patent No. 44 08 009 A1, describes a direct current power supply unit which consists of an input stage for filtering and rectifying the input voltage, a transformer stage for the DC/DC conversion of the input voltage, and at least one output stage for smoothing and generation of the desired output voltage. An energy storage mechanism is located between the transformer stage and the output stage. The energy storage mechanism thereby makes available an essentially constant intermediate voltage for the output stage.
European Patent No. 0 448 908 A1 also describes a method for the generation of a stable DC voltage and a stable DC voltage source. The DC voltage source consists essentially of an inductance. To the inductance a switching element or make-break unit, which switching element can be controlled, has been connected in series. This device generates an approximately constant DC average value by means of the controllable switching element and a current discriminator circuit.
Both of the embodiments described above have the disadvantage that they are relatively complex and expensive.